Conditioning, or “engine” is a fundamental aspect of fitness, for both the serious competitor and the person competing only against themselves. The MetCons or WODs encountered in most CrossFit boxes provide considerable conditioning benefit for the untrained person, but an avid participant will quickly approach a point of diminishing returns to their conditioning from this style of training alone. Improving beyond this point requires a dedicated effort outside the constraints of class.

A well designed conditioning program should target both anaerobic and aerobic energy systems. Measurement of power output (watts, calories, distance) is imperative for comparison across training sessions. Because our training is intended to develop broad, general fitness, multiple modalities should be included if possible. Common conditioning modalities include running, rowing, bike and swimming. If you incorporate swimming, you should be comfortable with the idea of being utterly exhausted in the water.

Anaerobic conditioning

Training anaerobic power is actually rather simple, though not easy. Anaerobic training should feature short, high intensity intervals. Rest between work intervals should be about 4-5 times the length of the work-interval. Any of the modalities (bike, run, swim, row) noted above are useful for anaerobic conditioning. One may perform different modalities within the same training session, but this can complicate performance measurement. Due to the high intensity of the intervals, athletes should also warmup thoroughly for any modality used in a training session. A sample anaerobic conditioning workout would be something like

5 rounds

Row 400m at 90-95% intensity

Rest 5 minutes

For most athletes, we suggest limiting anaerobic training to once per week. Despite the short work-duration, anaerobic conditioning is very taxing. The data points we rely on for anaerobic conditioning are (a) average work rate per interval and (b) difference between highest and lowest work rate in an interval. Effective anaerobic training increases the work rate while minimizing the difference between the work rate in each interval.

Aerobic conditioning

It is desirable for fitness athletes to devote the majority of conditioning time to aerobic power. Reasons for this include: (1) Most MetCons are fueled principally by aerobic power (2) Endurance is a key training parameter for aerobic capacity development, and developing endurance demands longer sessions and (3) Increasing aerobic power will decrease reliance on anaerobic power in most metcons; the reverse is not true

Aerobic conditioning is a little more complicated than anaerobic. A comprehensive aerobic program develops aerobic endurance (ability to sustain power for time) and aerobic power (the actual power produced, regardless of time). Collectively, we refer to these as aerobic capacity. At a minimum, an aerobic conditioning program should include, every week:

One endurance session. Novice athletes should start at modest durations (15-20 minutes) and build from there. More experienced athletes can go longer. For the novice, duration is paramount. Less experienced athletes must train their bodies to “go long”. We define the upper limit of duration training as 60 minutes. This is defined by the realities of the sport of fitness rather than any physiological limitation.

One speed / threshold session. This refers to a short duration aerobic-dominant workout at high intensity, sometimes called a "time trial". We prefer to start with at least 10 minutes, to minimize the relative contribution of the anaerobic system. Again, more experienced athletes will require longer sessions. Although the longer-term goal is to increase the duration of speed sessions, power output in speed sessions must remain consistent before duration increases.

One max-aerobic-power session. These sessions usually consist of short intervals with a 1:1 work to rest ratio. For example, in a 10-minute period, complete 10 intervals of work 30 seconds at high intensity and then rest 30 seconds. As conditioning levels increase, the number of intervals should increase, topping out at about 20-25 working intervals. To increase the stress of the max-aerobic power session, reduce the rest and lengthen the work period. However, refrain from this adjustment until the athlete can complete 20-25 intervals with no substantial power loss.

These three sessions, once per week, are minimum requirements for a good aerobic conditioning program. An aerobic program can incorporate more volume, based on athlete experience and fitness levels. An intermediate athlete can handle 4 training sessions per week, and work up to 5. Additional sessions beyond the three noted can be speed, interval or duration, depending on athlete tolerance. In general, we prefer not to add a second max-aerobic-power session, especially if the athlete is also including anaerobic conditioning as part of their training regime. Furthermore, each session should increase in duration and intensity as conditioning improves. As with anaerobic training, multiple modalities should be used if possible.

Implementation and management

As a general rule, there is no easily reached upper limit for aerobic endurance. Ironman, anyone? The one-hour limit is practical, not physiological. Over the very long term, the work rate of the speed sessions and duration sessions will converge at this one-hour upper limit. This means that the athlete will be able to sustain high power output (say, their rate of power output in a 10 or 15-minute session) for the entire hour. This idea of convergence introduces the The Gains Lab’s conditioning framework and the data points we use to implement it.

The three data points we use to measure aerobic capacity are endurance work rate, the speed work rate, and most importantly, the difference between them. For example, we recently tested an athlete’s endurance work rate (432 rowing cals in 30 mins, 14.4 cals/min), their speed work rate (171 rowing cals in 10 minutes; 17.1 cals/min). The difference between the two is 2.7 cals/min. Using only these data points, we can then gradually increase the duration of the speed training and endurance training, while monitoring the difference between them. The relationship among the data points allows us to easily adjust training and maximize gains with minimal guesswork.

Integration, testing and conclusions

By using the guidelines of (a) one anaerobic session per week and (b) one session each of duration work, speed work and max-aerobic power work, athletes at all levels should be able to manage a conditioning program (outside their traditional CrossFit program) suitable to their fitness level. Effective use of the three aerobic parameters simplifies performance management guides athletes and coaches toward their goals.

The most common mistake is doing too much too soon, especially regarding anaerobic conditioning. The idea that "strength training takes years but conditioning takes months" is absurd. In either discipline, it will require substantial time to achieve excellence. Be patient. The plan works if you do.

The efficacy of conditioning can and should be tested by not only session-to-session comparisons, but in benchmark MetCons and competitions to ensure carryover. Good luck and happy training.